Recently, the awareness of the ecological impact of providing telecommunication, operating associated telecommunication networks, and telecommunication in general, has risen amongst vendors of telecommunication equipment as well as network operators. In particular, the environmental aspect and ecological footprint of telecommunication technology has reached a pivotal significance that has already led to increased public funding of research initiatives directed to a sustainable usage of communication technology. Also, an enhanced commitment on sustainable technology can be observed from equipment manufacturers and vendors, who whish to market their products as environmentally friendly.
Since the power consumption of operating a telecommunication network may be substantial and also has become an important contributor to operating cost, operators begin to look for energy efficient network operation and network equipment. Such efforts may not only reduce operation cost drastically, but may also, on the other hand, be used by operators as a marketing instrument, such as employing environmentally friendly, energy efficient, equipment. An evaluation of the so called life-cycle-assessment (LCA), which includes also a measure of carbon dioxide emissions associated with providing network service to an average subscriber, shows that the required transmission power for transmitting data to a subscriber's mobile terminal may be a substantial contributor to the LCA footprint.
A known concept in the field of modern telecommunication system architecture is the so-called multi-access system architecture, where communication to user equipment (UE), such as a mobile terminal, may be conducted by more than one access network. In the following, the terms user equipment and mobile terminal will be used interchangeably. Multi-access capable mobile terminals may, therefore, not only communicate via a single access network, but may also employ a second, third or further access network for communication. Such a communication may, for example in the case of telephony, be forwarded further to a so-called core network which may be operated by a single network operator or service provider and may handle the communication to the mobile terminals. The core network is typically, in turn, further connected to other communication networks, such as PSTNs (Public Switched Telephone Networks), computer networks, such as the Internet, etc.
However, the possibility being given to UE or mobile terminals to use more than one access network for communication may require specific technical features in order to allow for a smooth and efficient network operation. Firstly, the UE should be able to discover the availability of other access networks in an efficient manner. For this reason, the UE can be provided with information about the availability of other access networks. Secondly, a suitable selection of one or more access networks from the available plurality of access networks should be made in order to allow for good communication service performance. Such selection is preferably controlled automatically, since most subscribers are not ready to deal manually with such technically complex issues.
Conventional concepts addressing the above issues include the so-called access network discovery and selection function (ANDSF), which has already been specified by the 3GPP collaboration. The concept thereof is, e.g., described in the technical specification documents 3GPP TS 23.402 VB.3.0 (2008-09), Technical Specification of the 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, Architecture enhancements for non-3GPP accesses TS-23402, and 3GPP TS 24.302 VI.2.0 (2008-11) Technical Specification of the 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Access to the 3GPP Evolved Packet Core (EPC) via non-3GPP access networks.